There used to be some excellent work by another member, however he used to post images on the SketchUcation forum using a link from photobucket; it’s some time later now and there seems to be a problem with the hosting of the images, as such only some links to external sources may be useful, if you have the time…

What is it you are really looking for? Free science fiction models you can use in SketchUp?

As for the Photobucket thing, Julian mentioned that some images wouldn’t be available due to Photobucket’s change or services which requires its users to pay for the ability to do third party sharing. That’s not Julian’s fault nor is it the fault of Sketchucation.